Add support for Intersil isl1208 RTC

Signed-off-by: Tor Krill <tor@excito.com>

README

@@ -669,6 +669,7 @@ The following options need to be configured:
 		CONFIG_RTC_DS1337	- use Maxim, Inc. DS1337 RTC
 		CONFIG_RTC_DS1338	- use Maxim, Inc. DS1338 RTC
 		CONFIG_RTC_DS164x	- use Dallas DS164x RTC
+		CONFIG_RTC_ISL1208	- use Intersil ISL1208 RTC
 		CONFIG_RTC_MAX6900	- use Maxim, Inc. MAX6900 RTC
 
 		Note that if the RTC uses I2C, then the I2C interface

drivers/rtc/Makefile

@@ -53,6 +53,7 @@ COBJS-y += rs5c372.o
 COBJS-y += rx8025.o
 COBJS-y += mcfrtc.o
 COBJS-y += x1205.o
+COBJS-$(CONFIG_RTC_ISL1208) += isl1208.o
 
 COBJS	:= $(COBJS-y)
 SRCS	:= $(COBJS:.o=.c)

drivers/rtc/isl1208.c

+/*
+ * (C) Copyright 2008
+ * Tor Krill, Excito Elektronik i Skåne , tor@excito.com
+ *
+ * Modelled after the ds1337 driver
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+/*
+ * Date & Time support (no alarms) for Intersil
+ * ISL1208 Real Time Clock (RTC).
+ */
+
+#include <common.h>
+#include <command.h>
+#include <rtc.h>
+#include <i2c.h>
+
+/*---------------------------------------------------------------------*/
+#ifdef DEBUG_RTC
+#define DEBUGR(fmt,args...) printf(fmt ,##args)
+#else
+#define DEBUGR(fmt,args...)
+#endif
+/*---------------------------------------------------------------------*/
+
+/*
+ * RTC register addresses
+ */
+
+#define RTC_SEC_REG_ADDR	0x0
+#define RTC_MIN_REG_ADDR	0x1
+#define RTC_HR_REG_ADDR		0x2
+#define RTC_DATE_REG_ADDR	0x3
+#define RTC_MON_REG_ADDR	0x4
+#define RTC_YR_REG_ADDR		0x5
+#define RTC_DAY_REG_ADDR	0x6
+#define RTC_STAT_REG_ADDR	0x7
+/*
+ * RTC control register bits
+ */
+
+/*
+ * RTC status register bits
+ */
+#define RTC_STAT_BIT_ARST	0x80	/* AUTO RESET ENABLE BIT */
+#define RTC_STAT_BIT_XTOSCB	0x40	/* CRYSTAL OSCILLATOR ENABLE BIT */
+#define RTC_STAT_BIT_WRTC	0x10	/* WRITE RTC ENABLE BIT */
+#define RTC_STAT_BIT_ALM	0x04	/* ALARM BIT */
+#define RTC_STAT_BIT_BAT	0x02	/* BATTERY BIT */
+#define RTC_STAT_BIT_RTCF	0x01	/* REAL TIME CLOCK FAIL BIT */
+
+static uchar rtc_read (uchar reg);
+static void rtc_write (uchar reg, uchar val);
+static uchar bin2bcd (unsigned int n);
+static unsigned bcd2bin (uchar c);
+
+/*
+ * Get the current time from the RTC
+ */
+
+void rtc_get (struct rtc_time *tmp)
+{
+	uchar sec, min, hour, mday, wday, mon, year, status;
+
+	status = rtc_read (RTC_STAT_REG_ADDR);
+	sec = rtc_read (RTC_SEC_REG_ADDR);
+	min = rtc_read (RTC_MIN_REG_ADDR);
+	hour = rtc_read (RTC_HR_REG_ADDR);
+	wday = rtc_read (RTC_DAY_REG_ADDR);
+	mday = rtc_read (RTC_DATE_REG_ADDR);
+	mon = rtc_read (RTC_MON_REG_ADDR);
+	year = rtc_read (RTC_YR_REG_ADDR);
+
+	DEBUGR ("Get RTC year: %02x mon: %02x mday: %02x wday: %02x "
+		"hr: %02x min: %02x sec: %02x status: %02x\n",
+		year, mon, mday, wday, hour, min, sec, status);
+
+	if (status & RTC_STAT_BIT_RTCF) {
+		printf ("### Warning: RTC oscillator has stopped\n");
+		rtc_write(RTC_STAT_REG_ADDR,
+			rtc_read(RTC_STAT_REG_ADDR) &~ (RTC_STAT_BIT_BAT|RTC_STAT_BIT_RTCF));
+	}
+
+	tmp->tm_sec  = bcd2bin (sec & 0x7F);
+	tmp->tm_min  = bcd2bin (min & 0x7F);
+	tmp->tm_hour = bcd2bin (hour & 0x3F);
+	tmp->tm_mday = bcd2bin (mday & 0x3F);
+	tmp->tm_mon  = bcd2bin (mon & 0x1F);
+	tmp->tm_year = bcd2bin (year)+2000;
+	tmp->tm_wday = bcd2bin (wday & 0x07);
+	tmp->tm_yday = 0;
+	tmp->tm_isdst= 0;
+
+	DEBUGR ("Get DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
+		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
+		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+}
+
+/*
+ * Set the RTC
+ */
+void rtc_set (struct rtc_time *tmp)
+{
+	DEBUGR ("Set DATE: %4d-%02d-%02d (wday=%d)  TIME: %2d:%02d:%02d\n",
+		tmp->tm_year, tmp->tm_mon, tmp->tm_mday, tmp->tm_wday,
+		tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
+
+	/* enable write */
+	rtc_write(RTC_STAT_REG_ADDR,
+		rtc_read(RTC_STAT_REG_ADDR) | RTC_STAT_BIT_WRTC);
+
+	rtc_write (RTC_YR_REG_ADDR, bin2bcd (tmp->tm_year % 100));
+	rtc_write (RTC_MON_REG_ADDR, bin2bcd (tmp->tm_mon));
+	rtc_write (RTC_DAY_REG_ADDR, bin2bcd (tmp->tm_wday));
+	rtc_write (RTC_DATE_REG_ADDR, bin2bcd (tmp->tm_mday));
+	rtc_write (RTC_HR_REG_ADDR, bin2bcd (tmp->tm_hour) | 0x80 ); /* 24h clock */
+	rtc_write (RTC_MIN_REG_ADDR, bin2bcd (tmp->tm_min));
+	rtc_write (RTC_SEC_REG_ADDR, bin2bcd (tmp->tm_sec));
+
+	/* disable write */
+	rtc_write(RTC_STAT_REG_ADDR,
+		rtc_read(RTC_STAT_REG_ADDR) & ~RTC_STAT_BIT_WRTC);
+}
+
+void rtc_reset (void)
+{
+}
+
+/*
+ * Helper functions
+ */
+
+static uchar rtc_read (uchar reg)
+{
+	return (i2c_reg_read (CFG_I2C_RTC_ADDR, reg));
+}
+
+static void rtc_write (uchar reg, uchar val)
+{
+	i2c_reg_write (CFG_I2C_RTC_ADDR, reg, val);
+}
+
+static unsigned bcd2bin (uchar n)
+{
+	return ((((n >> 4) & 0x0F) * 10) + (n & 0x0F));
+}
+
+static unsigned char bin2bcd (unsigned int n)
+{
+	return (((n / 10) << 4) | (n % 10));
+}